Trichinella pseudospiralis

Malone, Cody J., Oksanen, Antti, Mukaratirwa, Samson, Sharma, Rajnish & Jenkins, Emily, 2024, From wildlife to humans: The global distribution of Trichinella species and genotypes in wildlife and wildlife-associated human trichinellosis, International Journal for Parasitology: Parasites and Wildlife 24, pp. 100934-100934 : 100934-

3.4.3. Trichinella pseudospiralis in the Americas

Trichinella pseudospiralis was first reported in wildlife in the Americas in 1995 in Alabama, United States ( Lindsay et al., 1995). Since then, it has been reported elsewhere in the southern United States as well as on Vancouver Island, British Columbia in Canada in 2010 and the Northwest Territories in 2019 ( Table 20) ( Gajadhar and Forbes, 2010; Sharma et al., 2019). Trichinella pseudospiralis is a freeze-susceptible species which typically limits the northern geographic extent, but it has been reported in the subarctic of Canada in the Northwest Territories, possibly adventitiously introduced through migratory birds (Sharma et al., 2019). To date, there have been no reports of human infections attributed to T. pseudospiralis in the Americas, and it is the only species currently known to infect both mammals and birds in the Americas ( Gottstein et al., 2009; Pozio, 2016b).

3.5. Trichinella murrelli

Trichinella murrelli was first identified as a possible subspecies of Trichinella spiralis in 1987 by Dame et al., but was not fully described until 2000 ( Dame et al., 1987; Pozio and La Rosa, 2000). To date, T. murrelli has only been reported in southern Canada and the United States ( Feidas et al., 2014). The northern extent of T. murrelli may be limited by freeze susceptibility ( Gottstein et al., 2009). Trichinella murrelli primarily circulates among terrestrial omnivores and carnivores.

3.5.1. Trichinella murrelli in the Americas

The known distribution of T. murrelli is limited to the continental United States, from coast to coast, and the southern portions of two Canadian provinces (Ontario and British Columbia) ( Table 21). Trichinella murrelli does not develop in swine and thus poses low to no risk to people via consumption of pork products ( Gottstein et al., 2009). Only one human outbreak associated with T. murrelli has been reported in the Americas, from the consumption of black bear meat in Northern California ( Table 22).

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a T. nativa and T. britovi were genotyped but the number of positives for each host species were not reported.

b Proportion of animals positive for Trichinella spp . detected were reported, but not the amount of animals postive with each species.

c The proportion of T. nativa among all animals tested was 74%, but the exact proportion per host species was not reported.